diff --git a/Library/Homebrew/download_strategy.rb b/Library/Homebrew/download_strategy.rb
index 9b671d0a0b..0074b62ec7 100644
--- a/Library/Homebrew/download_strategy.rb
+++ b/Library/Homebrew/download_strategy.rb
@@ -491,7 +491,7 @@ class CurlDownloadStrategy < AbstractFileDownloadStrategy
         end
       end
 
-      filename ||= content_disposition.filename
+      filename = content_disposition.filename if filename.blank?
       next if filename.blank?
 
       # Servers may include '/' in their Content-Disposition filename header. Take only the basename of this, because: